Taiwan Patent No. 1271168 discloses a positioning mechanism for a slide assembly which is granted as U.S. Pat. No. 7,357,468, and generally includes a mediate rail and an inner rail which is simultaneously pulled out with the mediate rail. When the mediate rail is positioned relative to an outer rail, the inner rail is disengaged from the mediate rail and extended completely. When retracting the slide assembly, the inner rail and the mediate rail are retracted to the outer rail in sequence.
However, the second rail (mediate rail) cannot be locked relative to the first rail (outer rail) at the retracted status, and the second rail (mediate rail) cannot be unlocked individually and pulled with the third rail (inner rail). When the slide assembly is cooperated with a drawer or installed to a cabinet, the first rail (outer rail) is installed to the cabinet and connected to the second rail (mediate rail), and the third rail (inner rail) is connected with the drawer. The third rail (inner rail) is inserted to be connected or disengaged from the slide assembly relative to the second rail (mediate rail). When the third rail (inner rail) is to be disengaged from the second rail (mediate rail) to remove the drawer from the cabinet, the first action is to pull the third rail (inner rail) and the second rail (mediate rail) simultaneously from the first rail (outer rail), so that a part of the second rail (mediate rail) is pulled from the first rail (outer rail), and then, the third rail (inner rail) is completely pulled from the second rail (mediate rail). During the disengaging processes, the depth of the operation space has to be larger than the full length of the third rail (inner rail) plus the extended length of the second rail (mediate rail). When the space where a cabinet is placed is not enough to extend the third rail (inner rail) and the second rail (mediate rail), the kind of slide assembly is unsuitable for being used to the cabinet.
Accordingly, another slide assembly is needed to meet the requirement mentioned above.